1. Field of the Invention
The present invention relates, in general, to a sealing member or closure for a container and, more particularly, to a sealing member that includes a tab to facilitate removal of the sealing member.
2. Description of Related Art
It is often desirable to seal a bottle, jar or other container with a closure to maintain freshness of the contents thereof or to indicate whether the container has been tampered with. However, it is also desirable that the closure be easy to remove by the user. For example, U.S. Pat. No. 5,433,992 to Galda et al. describes a top-tabbed closure for a container which has a membrane for sealing the container and a sheet which is bonded to the top of the membrane, in a manner which leaves a tab portion of the sheet free. A user seeking to gain access to the contents of the container simply grips the tab with their fingers and by pulling on the tab, which is connected to the sheet, can remove the entire closure and access the contents of the container in a relatively convenient manner.
Referring generally to FIG. 1, a conventional top-tabbed closure is shown generally at the top of a bottle 10 as container seal 100. A cross-sectional view of seal 100, taken along line 2-2 of FIG. 1, which is not drawn to scale, is shown in FIG. 2.
Seal 100 includes a lower section 101, comprising a lower layer 110 which is formed of an adhesive, such as a hot melt adhesive or other sealants, for securing seal 100 to the top of bottle 10. Lower section 101 also includes a foil layer 120 and a polyethylene terephthalate (PET) layer 130 between foil layer 120 and lower layer 110. Seal 100 also includes an upper section 102 which includes an ethylene vinyl acetate (EVA) layer 170 having a PET top layer 180 disposed thereon. A bottom surface 150 of EVA layer 170 is surface treated and bonded to foil layer 120. Bottom surface 150 also bonds a paper release layer 140 to EVA layer 170. Thus, release layer 140 prevents EVA layer 170 from being completely bonded to foil layer 120 at lower surface 150. Bottom surface 150 only bonds EVA layer 170 to foil layer 120 up to a boundary line 160 so as to permit a tab portion 200 to be graspable. However, this bond between upper section 102 and lower section 101 is strong enough, so that pulling tab portion 200 can remove all of seal 100 in one piece.
Conventional container seals can exhibit disadvantages. For example, a paper release or information layer can be sensitive to exposure to moisture. Additionally, the use of PET release layers alone does not provide a fully satisfactory seal. Corrosion of foil layers can also present a problem. Also, conventional closures typically require containers to have smooth surfaces to insure proper bonding and release. Uneven heating during heat sealing steps has also occurred. Many closures will not separate from the container satisfactorily when the tab is pulled, and tearing and unsatisfactorily incomplete removal has occurred.
Accordingly, a need exists for an improved container seal which overcomes the above-described drawbacks and provides advantages compared to conventional container seals.